Other organisms used for toxicity testing

Although there are reservations about using Microtox as the primary test in the USA, it is considered useful in species sensitivity comparisons (Ankley et al., 1990, 1992 Bleckmann et al., 1996 Gupta and Karuppiah, 1996a,b). The Microtox test is sensitive to certain toxicants but relatively insensitive to other toxicants, including ammonia. Ammonia is a common toxicant in water and sediment samples (Schot et al., 1995). Microtox often fails to identify ammonia as the toxicant at concentrations toxic to most other aquatic organisms. As a result, when Microtox is used in combination with other species tests, its relative insensitivity to ammonia may lead to results that provide information on toxicants that may be masked by ammonia when only traditional species are used. 

Recently a move towards the assessment of cellular damage, chemical effects on enzyme or stress proteins and the relationship towards environmental assessments of contaminants have become more accepted within the regulatory 

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